The Center for Public Integrity determined the top donors on state-level races in the 2014 elections by looking at three destinations for giving: candidates’ campaigns, state political parties, and independent groups that typically campaign for or against candidates.

The Center defined state-level races as any statewide elective office plus all legislative seats up for election in 2014. New Jersey and Mississippi are not included because they did not have elections. If spouses gave jointly at all, reporters combined all of their contributions together.

The Center analyzed contributions made in 2013 and 2014 to candidates running in 2014 state-level elections and to state political parties, using data collected and processed as of Jan. 12, 2015, by the National Institute on Money in State Politics.

Additionally, the Center collected and analyzed contribution data from state campaign finance agencies, the Federal Election Commission and the Internal Revenue Service for 140 independent political groups active at the state level, as identified through political TV advertising data from media tracking firm Kantar Media/CMAG.

Such data provide a picture of the donations but it is imperfect. Some additional independent groups identified by Kantar Media/CMAG were not included in these calculations because they are not required to disclose their funders.

Additionally, varying campaign finance deadlines mean some contribution reports had not been filed by the cutoff date of Jan. 12 with state agencies or processed by the National Institute on Money in State Politics. Nationally, the National Institute data set included 80 percent of the available state reports for state parties and candidates. The completion rate for candidates' and state parties’ reports varies by state.